Drain plug assembly and system incorporating the same

ABSTRACT

An assembly for draining fluid from a sump having a receiver. A plug is adapted for threaded engagement with the receiver, has a transverse outlet arranged for communication with the sump, and is rotatable between: sealed, where flow is inhibited across the outlet; and drain, where fluid from the sump flows across the outlet. A head is rotatably attached to the plug. A limiter between the head and plug operates in: lock, where the head and plug rotate concurrently in a first direction to move the plug from sealed to drain; slip, where the head rotates in a second direction independent of the plug in response to torque acting on the head exceeding a threshold; and limit, where the head and plug rotate concurrently in the second direction in response to torque acting on the head being less than the threshold to move the plug towards sealed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application claims priority to and all the benefits of U.S. Provisional Patent Application No. 62/382,888, filed on Sep. 2, 2016, the disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates, generally, to sump drain plugs and, more specifically, to a drain plug assembly and system for draining fluid from a vehicle sump.

2. Description of the Related Art

Conventional automotive powertrain systems employ different types of fluids to facilitate lubrication, heat transfer, and the like throughout various components in use. By way of example, automotive engines circulate lubricating oil stored in a sump, such as an oil pan, using an oil pump which displaces the lubricating oil from the oil pan to various rotating assemblies of the engine, such as crankshaft and/or camshaft bearings, and the lubricating oil subsequently returns to the sump. It will be appreciated that lubricating oil is subjected to heat and wear in use, and may become contaminated by exposure to particulates and/or engine fuel and exhaust vapors. As such, engine lubricating oil is routinely changed to ensure long life and efficient performance of the engine. To this end, conventional automotive engine oil pans employ a drain hole arranged to allow lubricating oil to flow out of the oil pan, and a drain plug which is threaded into the drain hole to prevent lubricating oil from flowing out of the drain hole between lubricating oil changes.

During an oil change, the drain plug is removed from the oil pan and lubricating oil flows out of the drain hole. Typically, lubricating oil begins to flow immediately when the drain plug is removed. Used lubricating oil drained from the oil pan is captured and discarded, and the drain plug is cleaned and re-installed into the drain hole of the oil pan, typically along with a gasket or washer, to a predetermined torque. After the cleaned drain plug is properly installed, the engine is filled with new lubricating oil which flows into the oil pan and remains in the oil pan until it is subsequently changed again.

Conventional automotive oil pans are typically manufactured from metal, such as steel or aluminum, using a stamping or casting process. The drain hole may be machined or “tapped” into the oil pan, or may be formed in a separate “bung” that is subsequently attached to the oil pan, such as by welding. Irrespective of the specific material used, it will be appreciated that threaded components, such as drain plugs and oil pan drain holes, may become damaged during installation or removal of the drain plug during oil changes. By way of example, drain plugs may become damaged by “rounding-off” caused by using an incorrectly-sized removal tool or by “cross-threading” caused by improper installation, and oil pans may be damaged by “over-torqueing” the drain plug during installation. “Over-torqueing” the drain plug during installation may result in irreparable damage to the oil pan, such as a crack in the oil pan or stripped drain hole threads, which necessitates replacing the oil pan itself. It will be appreciated that oil pan replacement may be cumbersome due to engine orientation and/or vehicle configuration, as well as expensive where the oil pan is manufactured with complex geometry and/or from expensive materials. Moreover, replacement oil pans may not be stocked or otherwise readily available for certain vehicles or applications, which may result in significant down-time while a new oil pan is sourced to replace a damaged one.

While oil pans and drain plugs known in the related art have generally performed well for their intended use, there remains a need in the art for a drain plug assembly for a vehicle sump which ensures proper functionality during servicing and which affords opportunities for the use of improved oil pan technology while, at the same time, reducing the cost and complexity of manufacturing and servicing vehicle powertrain systems.

SUMMARY OF THE INVENTION

The present invention overcomes the disadvantages in the related art in a drain plug assembly for use in draining fluid out of a receiver operatively attached to a sump. The drain plug assembly includes a plug adapted for threaded engagement with the receiver. The plug has a transverse outlet arranged for fluid communication with the sump, and is rotatable about an axis between: a sealed position where fluid in the sump is inhibited from flowing across the outlet, and a drain position where fluid in the sump is permitted to flow across the outlet transverse to the axis. A head is coupled to the plug and is arranged for rotation in opposing first and second rotational directions in response to rotational torque applied to the head. A torque limiter is interposed between the head and the plug, and is operable between a lock configuration, a limit configuration, and a slip configuration. In the lock configuration, the head and the plug rotate concurrently in the first rotational direction to move the plug toward the drain position in response to rotational torque applied to the head in the first rotational direction. In the limit configuration, the head and the plug rotate concurrently in the second rotational direction to move the plug toward the sealed position in response to rotational torque applied to the head in the second rotational direction being less than a predetermined torque threshold. In the slip configuration, the head rotates independent of the plug in the second rotational direction to interrupt rotation of the plug in response to rotational torque applied to the head in the second rotational direction being greater than the predetermined torque threshold.

In addition, the present invention is also directed towards a system for use in draining fluid from a sump. The system includes a receiver adapted for attachment to the sump and extends along an axis between opposing first and second ends. A bore extends between the first end and the second end of the receiver. A drain port is arranged between the first end and the second end, and is disposed in fluid communication with the bore. The receiver includes a first seal surface arranged between the first end and the drain port, and a second seal surface arranged between the drain port and the second end. The system also includes a drain plug assembly for draining fluid from the sump. The drain plug assembly includes a seal arranged for engagement with the first and second seal surfaces of the receiver. A plug supports the seal, is disposed in threaded engagement with the receiver, and has an outlet arranged for fluid communication with the sump. The plug is rotatable about the axis between: a sealed position where the seal engages the first seal surface of the receiver to inhibit fluid in the sump from flowing across the outlet, and a drain position where the seal engages the second seal surface of the receiver to allow fluid in the sump to flow across the outlet and out of the drain port of the receiver. A head is coupled to the plug and is arranged for rotation in opposing first and second rotational directions in response to rotational torque applied to the head. A torque limiter is interposed between the head and the plug. The torque limiter is configured to translate applied rotational torque from the head to the plug to move the plug between the sealed position and the drain position. The torque limiter is further configured to interrupt rotation of the plug in response to rotational torque applied to the head exceeding a predetermined torque threshold.

In this way, the system and drain plug assembly of the present invention overcome the disadvantages in the prior art by securing fluid in the sump and allowing the sump to be drained of fluid in a simple and efficient way while, at the same time, ensuring that the plug can be subsequently tightened so as to retain fluid in the sump without risk of damage to the sump by overtightening. Moreover, the present invention affords opportunities for the use of sumps with improved features such as complex geometry and/or the use of composite materials while, at the same time, reducing the cost and complexity of manufacturing and servicing vehicle powertrain systems.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawings.

FIG. 1A is a perspective view of a sump, a receiver operatively attached to the sump, and a drain plug assembly secured to the receiver in a sealed configuration, according to one embodiment of the present invention.

FIG. 1B is a perspective view of the sump, the receiver, and the drain plug assembly of FIG. 1A shown with the drain plug assembly secured to the receiver in a drain configuration.

FIG. 1C is a perspective view of the sump, the receiver, and the drain plug assembly of FIGS. 1A-1B shown with the drain plug assembly removed from the receiver.

FIG. 2 is a partial top-side view of the drain plug assembly, the receiver, and a portion of the sump of FIG. 1A.

FIG. 3A is a sectional view of the sump and the receiver taken along line 3A-3A of FIG. 2 showing the drain plug assembly in section, with the drain plug assembly arranged in the sealed configuration as depicted in FIG. 1A.

FIG. 3B is another sectional view of the sump and the receiver taken along line 3A-3A of FIG. 2 showing the drain plug assembly in section, with the drain plug assembly arranged in the drain configuration as depicted in FIG. 1B.

FIG. 3C is another sectional view of the sump and the receiver taken along line 3A-3A of FIG. 2 showing the drain plug assembly in section, with the drain plug assembly removed from the receiver as depicted in FIG. 1C.

FIG. 4 is a perspective view of the receiver and the drain plug assembly of FIGS. 1A-3C, with the drain plug assembly arranged in the sealed configuration as depicted in FIG. 1A.

FIG. 5 is another perspective view of the receiver and the drain plug assembly of FIG. 4.

FIG. 6 is an exploded perspective view of the drain plug assembly and the receiver of FIGS. 4-5, the drain plug assembly shown having a seal, a plug, and a head.

FIG. 7 is another exploded perspective view of the receiver and the drain plug assembly of FIG. 6.

FIG. 8 is a top-side view of the receiver and the drain plug assembly of FIGS. 4-7.

FIG. 9 is a sectional view of the receiver and the drain plug assembly taken along line 9-9 of FIG. 8.

FIG. 10 is a sectional view of the receiver and the drain plug assembly taken along line 10-10 of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, where like numerals are used to designate like structure throughout the several views, a sump is illustrated at 20 in FIGS. 1A-1C. The sump 20 is configured to store or otherwise accommodate fluid, such as lubricating oil or coolant, for circulation such as by a pump to one or more components of an automotive engine or powertrain system (not shown, but generally known in the related art). In the representative embodiment illustrated herein, the sump 20 is realized as an oil pan with four generally-rectangular sump walls 22 which extend between and merge with a sump floor 24 and a flange 26. In the illustrated embodiment, the flange 26 of the sump 20 is adapted to be secured to a block of an engine, a transmission, and the like (not shown, but generally known in the related art). The sump walls 22 depend from the flange 26 and merge with the sump floor 24 to define a fluid reservoir configured to store engine oil. However, as will be appreciated from the subsequent description below, the sump 20 could have a number of different shapes and/or configurations without departing from the scope of the present invention

A boss, generally indicated at 28, is formed in one of the sump walls 22 and is arranged to promote fluid draining, such as with the assistance of gravity. Here too, it will be appreciated that the boss 28 could be disposed in a number of suitable locations, such as in the sump floor 24. As is described in greater detail below, the boss 28 defines an aperture 30 in which a receiver 32 is supported. The receiver 32, in turn, is operatively attached to the sump 20 and cooperates with a drain plug assembly, generally indicated at 34, to allow fluid to be drained from the sump 20. More specifically, the receiver 32 and the drain plug assembly 34 cooperate to define a system, generally indicated at 36, for use in draining fluid from the sump 20, according to one embodiment of the present invention. In the representative embodiment illustrated herein, the receiver 32 is formed as a separate component from the sump 20 and is operatively attached to the sump 20 such as via welding, adhesive bonding, and the like. However, those having ordinary skill in the art will appreciate that the receiver 32 could be formed integrally with the sump 20 which, in turn, can be configured with or without the use of a discrete boss 28 or aperture 30, without departing from the scope of the present invention. Both the receiver 32 and the drain plug assembly 34 of the system 36 will be described in greater detail below.

As noted above, the sump 20 illustrated herein is realized as a generally-rectangular shaped oil pan employed to store engine oil for an engine of an automotive passenger vehicle, and is configured to removably attach to the engine block via the flange 26. However, those having ordinary skill in the art will appreciate that the sump 20 illustrated herein is conventional, is depicted and described generically, does not form a part of the present invention, and could be of any suitable size, type, configuration, or arrangement sufficient to store any suitable type of fluid used in any suitable type of fluid system, of any suitable type of vehicle, engine, powertrain, and the like, without departing from the scope of the present invention. By way of non-limiting example, the sump 20 could be used to store gear oil, hydraulic fluid, transmission fluid, engine coolant, power steering fluid, water, washer fluid, Diesel Exhaust Fluid (DEF), gasoline or diesel fuel, or any other fluid intended to be periodically drained from the sump 20. Moreover, as will be appreciated from the subsequent description below, the present invention is not limited for use with oil pans of automotive passenger vehicles and may be implemented in connection with sumps 20 of any suitable type of vehicle, engine, or fluid system, such as may be utilized in connection with heavy-duty trucks, trains, airplanes, ships, construction vehicles or equipment, military vehicles, and the like.

As noted above, the system 36 illustrated in FIGS. 1A-1C is provided for use in draining fluid from the sump 20, and includes the receiver 32 and the drain plug assembly 34. The receiver 32 is adapted to be operatively attached to the sump 20. The receiver 32 extends along an axis AX between a first end 32A and an opposing second end 32B. The receiver 32 has a bore, generally indicated at 38, formed extending between the first end 32A and the second end 32B of the receiver 32. As is described in greater detail below, the receiver 32 also comprises a seal surface, generally indicated at 40, which cooperates with the drain plug assembly 34 to limit, prevent, or otherwise restrict the flow of fluid out of the sump 20.

In one embodiment, the drain plug assembly 34 includes a seal 42, a plug 44, a head 46, and a torque limiter 48. The seal 42 is arranged for engagement with the seal surface 40 of the receiver 32. As is described in greater detail below, in one embodiment of the present invention, the seal surface 40 of the receiver 32 comprises a first seal surface 40A arranged to engage the seal 42 to inhibit the flow of fluid out of the sump 20, and a second seal surface 40B arranged to engage the seal 42 to help direct the flow of fluid draining from the sump 20. For the purposes of clarity and consistency, and unless otherwise indicated herein, the term seal surface 40 refers to any suitable portion of the receiver 32 which engages the seal 42 to prevent fluid from flowing out of the sump 20, such as the first seal surface 40A.

The plug 44 supports the seal 42, is adapted for threaded engagement with the receiver 32, and has a transverse outlet 50 arranged for fluid communication with the sump 20. The plug 44 is rotatable about the axis AX between a sealed position 44A where the seal 42 is compressed between the plug 44 and the seal surface 40 of the receiver 32 such that fluid in the sump is inhibited from flowing across the outlet 50 (see FIGS. 1A and 3A), and a drain position 44B where fluid in the sump 20 is permitted to flow across the outlet 50 (see FIGS. 1B and 3B).

As is described in greater detail below, the head 46 of the drain plug assembly 34 is configured to be rotated via applied rotational torque, such as from a wrench, a socket, and the like (not shown, but generally known in the art). The head 46 of the drain plug assembly 34 is coupled to the plug 44 and is arranged rotation in a first rotational direction RD1 and in an opposite second rotational direction RD2 in response to rotational torque applied to the head 46.

The torque limiter 48 of the drain plug assembly 34 is interposed in force-translating relationship between the head 46 and the plug 44. As is described in greater detail below, the torque limiter 48 is configured to translate rotational torque acting on or otherwise applied to the head 46 into the plug 44 so as to move the plug 44 between the sealed position 44A and the drain configuration 44B, and is also configured to interrupt rotation of the plug 44 in response to rotational torque acting on or otherwise applied to the head 46 which exceeds a predetermined torque threshold. Put differently, when rotational torque is applied to the head 46, the torque limiter 48 allows the plug 44 and the head 46 to rotate concurrently so long as the applied rotational torque is less than the predetermined torque threshold. If rotational torque is applied to the head 46 in excess of the predetermined torque threshold, the torque limiter 48 will not allow the plug 44 to rotate concurrently with the head 46.

In certain embodiments of the present invention, the torque limiter 48 is operable between a lock configuration 48A, a slip configuration 48B, and a limit configuration 48C. In the lock configuration 48A, the head 46 and the plug 44 rotate concurrently in the first rotational direction RD1 in response to rotational torque applied to the head 46 in the first rotational direction RD1 such that concurrent rotation of the head 46 and the plug 44 in the first rotational direction RD1 moves the plug 44 from the sealed position 44A to the drain position 44B (compare FIGS. 1A and 3A to FIGS. 1B and 3B). In the slip configuration 48B, the head 46 rotates in the second rotational direction RD2 independent of the plug 44 in response to rotational torque applied to the head 46 in the second rotational direction RD2 exceeding a predetermined torque threshold. In the limit configuration 48C, the head 46 and the plug 44 rotate concurrently in the second rotational direction RD2 in response to rotational torque applied to the head 46 in the second rotational direction RD2 being less than the predetermined torque threshold such that concurrent rotation of the head 46 and the plug 44 in the second rotational direction RD2 moves the plug 44 towards the sealed position 44A (compare FIGS. 1B and 3B to FIGS. 1A and 3A). Each of the components of the system 36 introduced above will be described in greater detail below.

As noted above, the drain plug assembly 34 is configured to be received by the receiver 32 such that threaded engagement between the plug 44 of the drain plug assembly 34 and the receiver 32 facilitates movement between the sealed position 44A and the drain position 44B as rotational torque is applied to the head 46. To this end, as best shown in FIGS. 4-7, the receiver 32 includes a pair of thread teeth, generally indicated at 52, which project radially-inwardly towards each other into the bore 38, and the plug 44 includes a shank, generally indicated at 54, in which a pair of threaded grooves, generally indicated at 56, are formed. In addition to the shank 54, the plug 44 also includes a mount 58 and a coupler 60. The mount 58 is configured to support the seal 42 and is arranged axially between the shank 54 and the coupler 60. The coupler 60 is arranged to support the head 46 for rotation about the axis AX and is shaped to inhibit axial movement of the head 46 with respect to the plug 44, as described in greater detail below. The shank 54 extends along the axis AX to a shank end 62. The outlet 50 is formed in the shank 54 axially between the shank end 62 and the mount 58, and is radially spaced between the threaded grooves 56. In one embodiment, the outlet 50 is formed in the shank 54 arranged axially between the shank end 62 and the head 46, and is formed transverse to the axis AX so as to direct fluid flowing from the sump 20 and across the outlet 50 away from the axis AC when the plug 44 is in the drain position 44B (FIGS. 1B and 3B).

The threaded grooves 56 of the shank 54 of the plug 44 engage and receive the thread teeth 52 of the receiver 32 such that relative rotation between the receiver 32 and the plug 44 causes corresponding relative movement of the thread teeth 52 along the threaded grooves 56. More specifically, because the receiver 32 is fixed to the sump 20, as described in greater detail below, rotation of the plug 44 in the first rotational direction RD1 urges the mount 58 and the seal 42 axially away from the seal surface 40, and rotation of the plug 44 in the second rotational direction RD2 urges the mount 58 and the seal 42 axially towards the seal surface 40, because of the threaded engagement between the thread teeth 52 of the receiver 32 and the threaded grooves 56 of the shank 54 of the plug 44 of the drain plug assembly 34. As will be appreciated from the subsequent description below, the threaded grooves 56 and/or the thread teeth 52 can be configured or otherwise arranged in a number of different ways without departing from the scope of the present invention. By way of non-limiting example, teeth could be formed in the plug 44 and correspondingly-shaped grooves could be formed in the receiver 32.

Because the outlet 50 is spaced axially away from the seal 42 along the shank 54, as well as axially away from the seal surface 40 of the receiver 32, when the plug 44 is in the sealed position 44A, compression of the seal 42 between the mount 58 of the plug 44 and the seal surface 40 of the receiver 32 ensures that fluid cannot flow through the outlet 40 when the plug 44 is in the sealed position 44A, as noted above (see FIGS. 1A and 3A). Moreover, because of the relative axial position of the outlet 50 along the shank 54, fluid can flow out of the outlet 50 from the sump 20 when the plug 44 is in the drain position 44B, as noted above and as is described in greater detail below (see FIGS. 1C and 3C).

In order to facilitate fluid communication between the outlet 50 of the plug 44 and the sump 20 when the plug 44 is in the drain position 44B, in one embodiment, the shank 54 of the plug 44 extends axially away from the mount 58 to the shank end 62. Here, an inlet 64 is formed in the shank 54 adjacent to the shank end 62, and a channel 66 is formed in the shank 54 extending in fluid communication between the inlet 64 and the outlet 50 to permit fluid in the sump 20 to flow across the inlet 64, along the channel 66, and across the outlet 50 when the plug 44 is in the drain position 44B. In the representative embodiment illustrated herein, the channel 66 has a substantially cylindrical profile which extends along the axis AX so as to be concentrically aligned with the shank 54 of the plug 44. The channel 66 merges with the outlet 50 at a location adjacent to and spaced axially from the mount 58 and the seal 42. As noted above, the outlet 50 is formed transversely into the shank 54 of the plug 44 to direct fluid away from the axis AX and also has a substantially cylindrical profile. In the illustrated embodiment, the outlet 50 is formed generally perpendicular to the axis AX.

As is shown best in FIG. 3B, in the illustrated embodiment, a pair of outlets 50 are provided in fluid communication with the sump 20. Here, an outlet channel 68 extends between the outlets 50 and is arranged in fluid communication with the channel 66 to facilitate concurrent fluid communication of the outlets 50 with the sump 20. This configuration affords a symmetric profile which ensures that fluid can flow across one of the outlets 50 when the plug 44 is in the drain position 44B irrespective of which threaded groove 56 engages which thread tooth 52. However, as will be appreciated from the subsequent description below, a single outlet 50 formed transversely into the plug 44 and arranged in fluid communication with the sump 20 could be employed in some embodiments. Moreover, while the plug 44 in the illustrated embodiment is provided with a single inlet 64 formed at the shank end 62, it will be appreciated that one or more inlets 64 could be provided in different locations sufficient to communicate with one or more outlets 50 across one or more channels 66 of any suitable shape, orientation, or configuration, without departing from the scope of the present invention.

As noted above, the receiver 32 extends along the axis AX between opposing first and second ends 32A, 32B, and the bore 38 is formed extending through the receiver 32. As best shown in FIGS. 7-9, the receiver 32 is formed as a unitary, one-piece component with a first cylindrical region 70 having a first inner diameter 70A and a first outer diameter 70B, a second cylindrical region 72 having a second inner diameter 72A and a second outer diameter 72B, and a tapered region 74 extending between the first cylindrical region 70 and the second cylindrical region 72 (see FIG. 9). Here, the first inner diameter 70A is smaller than the second inner diameter 70B. However, the difference between the first inner diameter 70A and the first outer diameter 70B is substantially equal to the difference between the second inner diameter 70A and the second outer diameter 70B, giving the receiver 32 a substantially consistent wall thickness 76 across each of the regions 70, 72, 74 in the illustrated embodiment. However, as will be appreciated from the subsequent description below, in some embodiments the receiver 32 could be shaped or otherwise configured in a number of different ways, such as with a varying wall thickness 72 between the first and second ends 32A, 32B, or with a generally consistent inner diameter. Other configurations are contemplated.

In the representative embodiment illustrated herein, the receiver 32 is provided with a drain port, generally indicated at 78, which is arranged between the first end 32A and the second end 32B of the receiver 32 and extends in fluid communication with the bore 48. Like the outlet 50 of the plug 44, the drain port 78 of the receiver 32 is similarly formed transverse to the axis AX. Here, the drain port 78 is advantageously arranged so as to be at least partially aligned with the outlet 50 of the plug 44 when the plug 44 is in the drain position 44B (see FIG. 3B). This configuration helps promotes the flow of fluid downwardly out of the drain port 78 from the outlet 50, which significantly improves the ability to direct used fluid draining out of the sump 20 in a predictable manner, thereby contributing to improved cleanliness during sump 20 draining.

As noted above, the receiver 32 is provided with the first seal surface 40A and the second seal surface 40B in the illustrated embodiment. As is depicted in FIGS. 3A-3C, the first seal surface 40A is arranged between the first end 32A of the receiver 32 and the drain port 78, and the second seal surface 40B is arranged between the drain port 78 and the second end 32B of the receiver 32. Because the seal 42 is supported by the mount 58 for concurrent movement with the plug 44, the seal 42 engages the first seal surface 40A of the receiver 32 when the plug 44 is in the sealed position 44A (see FIG. 3A) so as to inhibit fluid in the sump 20 from flowing across the outlet 50. Conversely, the seal 42 engages the second seal surface 40B of the receiver 32 when the plug 44 is in the drain position 44B (see FIG. 3B) so as to allow fluid in the sump 20 to flow across the outlet 50 and out of the drain port 78 of the receiver 32.

The bore 38 of the receiver 32 has a stepped configuration defined by the first and second cylindrical regions 70, 72, and the tapered region 74, as noted above. In one embodiment, the first cylindrical region 70 of the bore 38 adjacent to the first end 32A of the receiver 32 at least partially defines the first seal surface 40A, and the second cylindrical region 72 of the bore 38 adjacent to the second end 32B of the receiver 32 at least partially defines the second seal surface 40B (see FIGS. 3A-3B).

In the representative embodiment illustrated herein, the seal 42 is realized as an O-ring and the mount 58 of the plug 44 is realized as a groove formed in the plug 44 axially adjacent to the outlet 50 which supports the seal 42. This configuration promotes concurrent axial movement between the seal 42 and the plug 44 as the plug 44 moves between the position 44A, 44B, as noted above. As shown in FIGS. 6-7, the seal 42 has a substantially toroidal configuration with an outer seal diameter 42A and an inner seal diameter 42B. The outer seal diameter 42A is larger than the first inner diameter 70A of the first cylindrical region 70 of the bore 38 of the receiver 32 such that the seal 42 is compressed between the plug 44 and the first seal surface 40A of the receiver 32 when the plug 44 is in the sealed position 44A to prevent fluid from flowing across the outlet 50 out of the sump 20 (see FIG. 3A). Here, when the seal 42 is compressed between the plug 44 and the first seal surface 40A of the receiver 32, the seal 42 has a generally oval cross-sectional profile. The outer seal diameter 42A is also larger than the second inner diameter 72A of the second cylindrical region 72 of the bore 38 of the receiver 32 such that the seal 42 is at least partially compressed between the plug 44 is in the drain position 44B to prevent fluid in the sump 20 from flowing out of the second end 32B of the receiver 32 (see FIG. 3B) as fluid from the sump 20 flows across the outlet 50 of the plug 44 and out of the drain port 78 of the receiver 32. Here too it will be appreciated that this arrangement significantly improves the ability to direct used fluid draining out of the sump 20 in a predictable manner, thereby contributing to improved cleanliness during sump 20 draining.

Because the drain port 78 of the receiver 32 is arranged axially between the first seal surface 40A and the second seal surface 40B, it will be appreciated that the seal 42 at least partially traverses the drain port 78 as the plug 44 moves between the sealed position 44A and the drain position 44B. In the illustrated embodiment, the drain port 78 of the receiver 32 is formed at least partially in the second cylindrical region 72 of the receiver 32 and is disposed in spaced relation with the first cylindrical region 70 of the receiver 32. The tapered region 74 of the bore 38 of the receiver 32 extends between the first and second cylindrical regions 70, 72, as noted above, and is shaped to promote consistent and reliable compression of the seal 42 between the plug 44 and the first cylindrical region 70 of the receiver 32 as the plug 44 moves toward the sealed position 44A (see FIG. 3A). However, those having ordinary skill in the art will appreciate that the seal surfaces 40A, 40B and the regions 70, 72, 74 of the receiver 32 could have any suitable shape or configuration sufficient to inhibit the flow of fluid from the sump 20 across the outlet 50 when the plug 44 is in the sealed position 44A without departing from the scope of the present invention. Furthermore, while the seal 42 is configured as an O-ring supported by the mount 58 of the plug 44 in the illustrated embodiment, other configurations are contemplated. By way of non-limiting example, the mount 58 could be realized as a stepped surface which abuts a portion of the seal 42 (not shown).

Referring to FIGS. 7-9, in one embodiment, the threaded grooves 56 of the plug 44 are formed helically about the shank 54 of the plug 44 so as to each define a respective seal stop portion 80, a drain stop portion 82, and a release portion 84. Here, the seal stop portions 80 are arranged to abut the respective thread teeth 52 of the receiver 32 when the plug 44 is in the sealed position 44A (see FIGS. 1A and 3A) so as to prevent subsequent rotation of the plug 44 in the second rotational direction RD1, but to allow for rotation of the plug 44 in the first rotational direction RD1 (see also FIGS. 4 and 7). When the plug 44 is rotated in the first rotational direction RD1 from the sealed position 44A, the thread teeth 52 come out of abutment with the seal stop portions 80 and travel helically along the threaded grooves 56 towards the drain stop portions 82, which causes the seal 42 to move axially away from the seal surface 40 to allow fluid communication across the outlet 50, as noted above.

The drain stop portions 82 of the plug 44 are arranged to abut the respective thread teeth 52 when the plug 44 is in the drain position 44B (see FIGS. 1B and 3B) so as to inhibit subsequent axial movement of the plug 44 away from the receiver 32 (see also FIG. 7). It will be appreciated that this configuration helps keep the drain plug assembly 34 retained axially by the receiver 32 when the plug 44 is in the drain position 44B, thereby allowing fluid to be drained from the sump 20 transversely (and, advantageously, downwardly) across the outlet 50 and out of the drain port 78 without necessitating complete axial removal of the drain plug assembly 34 from the receiver 32 while, at the same time, promoting flow of fluid out of the outlet 50 at a sufficient flowrate to empty the sump 20 of fluid quickly, efficiently, and in a controlled manner. However, as shown in FIG. 7, the release portions 84 of the threaded grooves 56 are arranged to permit removal of the drain plug assembly 34 from the receiver 32 after subsequent rotation of the plug 44 in the first rotational direction RD1, whereby the thread teeth 52 come out of abutment with the drain stop portions 82 and travel helically along the remainder of the threaded grooves 56 towards the release portions 84 which, in the illustrated embodiment, are disposed at the shank end 62 of the shank 54 and are configured to permit the plug 44 to be axially released from the receiver 32 such that the drain plug assembly 34 can be removed from the receiver 32 (see FIGS. 1C and 3C), such as to allow the seal 42 to be cleaned or replaced once the fluid has been drained from the sump 20.

While the representative embodiment of the system 36 described herein and depicted throughout the drawings includes a pair of threaded grooves 56 formed in the plug 44 and a corresponding pair of thread teeth 52 formed in the receiver 32, those having ordinary skill in the art will appreciate that any suitable threaded arrangement could be employed between the plug 44 and the bore 38 of the receiver 32 without departing from the scope of the present invention. By way of non-limiting example, a single threaded groove 56 and a single thread tooth 52 could be employed, or the plug 44 could include one or more teeth and the receiver 32 could include one or more threads for receiving the teeth (not shown).

Referring now to FIGS. 4-7 and 10, as noted above, the drain plug assembly 34 employs the torque limiter 48 to effect rotation control of the head 46 with respect to the plug 44. In the representative embodiment illustrated herein, the torque limiter 48 allows the plug 44 of the drain plug assembly 34 to be moved from the sealed position 44A to the drain position 44B without limiting the amount of torque translated between the head 46 and the plug 44 in the first rotational direction RD1, while conversely limiting the amount of torque translated between the head 46 and the plug 44 in the second rotational direction RD2 to prevent over-torqueing the plug 44 to the receiver 32 once the plug 44 reaches the sealed position 44A. To this end, in one embodiment, the torque limiter 48 includes a torque receiving element 86 operatively attached to the coupler 60 of the plug 44, and a torque delivery element 88 operatively attached to the head 46. The torque delivery element 88 is disposed in engagement with the torque receiving element 86 such that the head 46 and the plug 44 rotate concurrently in response to rotational torque applied to the head 46 in either of the first and second rotational directions RD1, RD2 being less than the predetermined torque threshold.

As best shown in FIG. 10, the torque receiving element 86 is realized as a sleeve 90 in which a plurality of splines 92 are arranged radially about the axis AX and extend inwardly toward the axis AX. The splines 92 each have a ramp surface 94 and a flat surface 96. The torque delivery element 88, in turn, is realized as a gear 98 from which a plurality of resilient cogs 100 are formed, spaced radially about the axis AX and extending outwardly from the axis AX. The resilient cogs 100 each have a brace surface 102 and a cam surface 104.

As is described in greater detail below, the resilient cogs 100 engage the splines 92 to facilitate concurrent rotation of the head 46 and the plug 44 when the torque limiter 48 operates in either the lock configuration 48A or the limit configuration 48C, and the resilient cogs 100 are shaped so as to deflect to interrupt concurrent rotation of the head 46 and the plug 44 when the torque limiter 48 operates in the slip configuration 48B. However, as will be appreciated from the subsequent description below, the torque limiter 48 could be configured in any suitable way sufficient to operate between the lock configuration 48A, the slip configuration 48B, and the limit configuration 48B described above without departing from the scope of the present invention.

As noted above, when the torque limiter 48 is in the lock configuration 48A, the head 46 and the plug 44 rotate concurrently in the first rotational direction RD1 in response to rotational torque applied to the head 46 in the first rotational direction RD1 such that concurrent rotation of the head 46 and the plug 44 in the first rotational direction RD1 moves the plug 44 from the sealed position 44A to the drain position 44B (compare FIGS. 1A and 3A to FIGS. 1B and 3B). To this end, and as is best shown in FIG. 10, each of the brace surfaces 102 of the resilient cogs 100 of the gear 98 of the torque delivery element 88 respectively abuts the flat surface 96 of one of the splines 92 of the torque receiving element 86 in response to rotation of the head 46 in the first rotational direction RD1. The abutment between the brace surfaces 102 and the flat surfaces 96 causes rotational torque applied to the head 46 in the first rotational direction RD1 to translate from the torque delivery element 88 to the torque receiving element 86. More specifically, because of the orientation and configuration of the brace surfaces 102 of the resilient cogs 100 of the gear 98 of the torque delivery element 88, and the corresponding orientation and configuration of the flat surfaces 96 of the splines 92 of the sleeve 90 of the torque receiving element 86, the abutment between the brace surfaces 102 and the flat surfaces 96 effects concurrent rotation of the head 46 and the plug 44 in the first rotational direction RD1 without torque limitation, during proper use of the system 36 (by way of example, improper use could be an extreme application of torque sufficient to break or otherwise damage one or more components of the system 36).

As noted above, when the torque limiter 48 is in the slip configuration 48B, the head 46 rotates in the second rotational direction RD2 independent of the plug 44 in response to rotational torque applied to the head 46 in the second rotational direction RD2 exceeding the predetermined torque threshold. To this end, in the representative embodiment illustrated herein and best shown in FIG. 10, each of the cam surfaces 104 of the resilient cogs 100 of the gear 98 of the torque delivery element 88 respectively comes into engagement with the ramp surface 94 of one of the splines 92 of the torque receiving element 86 in response to rotation of the head 46 in the second rotational direction RD2. Here, the engagement between the cam surfaces 104 and the ramp surfaces 94 causes the resilient cogs 100 of the gear 98 of the torque delivery element 88 to deflect radially inwardly and away from the splines 92 to bring the cam surfaces 104 out of abutment with the ramp surfaces 94 when rotational torque in excess of the predetermined torque threshold is applied to the head 46 in the second rotational direction RD2. Here, the inward radial deflection of the resilient cogs 100 allows the head 46 to rotate in the second rotational direction RD2 independent of the plug 44 when the predetermined torque threshold is exceeded. More specifically, because of the orientation and configuration of the cam surfaces surfaces 104 of the resilient cogs 100 of the gear 98 of the torque delivery element 88, and the corresponding orientation and configuration of the ramp surfaces 94 of the splines 92 of the sleeve 90 of the torque receiving element 86, the engagement between the cam surfaces 104 and the ramp surfaces 94 prevents torque exceeding the predetermined torque threshold from be applied to the plug 44 from the head 46 in the second rotational direction RD2.

As noted above, when the torque limiter 48 is in the limit configuration 48C, the head 46 and the plug 44 rotate concurrently in the second rotational direction RD2 in response to rotational torque applied to the head 46 in the second rotational direction RD2 being less than the predetermined torque threshold such that concurrent rotation of the head 46 and the plug 44 in the second rotational direction RD2 moves the plug 44 towards the sealed configuration (compare FIGS. 1B and 3B to FIGS. 1A and 3A). To this end, in the representative embodiment illustrated herein and best shown in FIG. 10, each of the cam surfaces 104 of the resilient cogs 100 of the gear 98 of the torque delivery element 88 respectively comes into abutment with the ramp surface 94 of one of the splines 92 of the torque receiving element 86 in response to rotation of the head 46 in the first rotational direction RD1. Here, the abutment between the cam surfaces 104 and the ramp surfaces 94 causes rotational torque applied to the head 46 in the second rotational direction RD2 which is less than the predetermined torque threshold to translate from the torque delivery element 88 to the torque receiving element 86. More specifically, because of the orientation and configuration of the cam surfaces 104 of the resilient cogs 100 of the gear 98 of the torque delivery element 88, and the corresponding orientation and configuration of the ramp surfaces 94 of the splines 92 of the sleeve 90 of the torque receiving element 86, the abutment between the cam surfaces 104 and the ramp surfaces 94 allows for torque less than the predetermined torque threshold to be applied to the plug 44 from the head 46 in the second rotational direction RD2. However, when the rotational torque applied to the head 46 in the second rotational direction RD2 exceeds the predetermined torque threshold, the torque limiter 48 moves from the limit configuration 48C to the slip configuration 48B described above.

With continued reference to FIG. 10, in the representative embodiment of the torque limiter 48 illustrated herein, a total of fifteen splines 92 are provided in the sleeve 90 of the torque receiving element 86 and a total of five resilient cogs 100 are provided on the gear 98 of the torque delivery element 88. However, those having ordinary skill in the art will appreciate different arrangements of splines 92 and/or resilient cogs 100 could be utilized, and could be sized or shaped in any suitable way sufficient to promote operation between the configurations 48A, 48B, 48C described above. Moreover, it will be appreciated that the arrangement and geometry of the resilient cogs 100 and/or the splines 92 can be configured differently, such as to set the predetermined torque threshold for different applications. Furthermore, while the splines 92 are formed in the plug 44 and the resilient cogs 100 are formed in the head 46 in the illustrated embodiment, it will be appreciated that this arrangement could be reversed without departing from the scope of the present invention.

Referring again to FIGS. 6 and 7, as noted above, the coupler 60 of the plug 44 is configured to rotatably secure the head 46. To this end, the coupler 60 is operatively attached to the plug 44 adjacent to the sleeve 90 and has a generally ring-shaped profile with at least one transverse slot 106 formed therethrough which partitions the coupler 60 into a plurality of coupler arc segments 108. In the representative embodiment illustrated herein, a pair of transverse slots 106 are provided to define two pairs of coupler arc segments 108. In one embodiment, at least one of the coupler arc segments 108 includes a retention lip 110 which defines a retention pocket 112 which accommodates and secures the head 46 to the plug 44 and allows for relative rotation therebetween. To this end, the head 46 includes an interface body 114 and a retention flange 116. The retention flange 116 is arranged axially between the interface body 114 and the gear 98, and has a generally cylindrical profile which is complementarily-shaped to the retention pocket 112 of the coupler 60. Here, the retention lip 110 of the coupler 60 of the plug 44 and the retention flange 116 of the head 46 are shaped so as to allow the head 46 to be installed into the coupler 60, whereby the gear 98 may be positioned within the sleeve 90 and the retention flange 116 brought into engagement with the retention lip 110 which, in response to axial force applied to the head 46, causes the coupler arc segment 108 with the retention lip 110 to resiliently deflect away to allow the retention flange 116 to enter the retention pocket 112 and subsequently resiliently return to retain the head 46 for rotation with respect to the plug 44, as described above.

The interface body 114 of the head 46 is configured to receive torque from a tool, such as a socket or wrench (not shown, but generally known in the art) so as to translate torque applied to the head 46 to the plug 44 across the torque limiter 48, as described above. In the representative embodiment illustrated herein, the interface body 114 has a generally cylindrical profile with rectangular recess 118 formed therein for receiving the tool. The interface body 114 also has a position indicator 120 extending outwardly therefrom which may be used as a reference for the relative rotational position of the head 46 in use. In the illustrated embodiment, the plug 44 is provided with a plug recess 122 to facilitate removal of the plug 44 if the drain plug assembly 34 is inadvertently damaged, such as where improper application of torque damages the head 46. Those having ordinary skill in the art will appreciate that the interface body 114, the recess 118, and/or the plug recess 122 could have any suitable shape, configuration, or profile sufficient to engage and receive torque from any suitable type of tool without departing from the scope of the present invention. By way of non-limiting example, the interface body 114 could be formed as a “bolt head” configured to be received by a conventional socket wrench (not shown). It will be appreciated that the head 46, like the plug 48 described above, is a unitary one-piece component.

In this way, the system 36 and drain plug assembly 34 of the present invention secure fluid in the sump 20 and allow the sump 20 to be drained of fluid in a simple and efficient way while, at the same time, ensuring that the sump 20 cannot be damaged due to overtightening. Specifically, it will be appreciated that the torque limiter 48 prevents the head 46 from translating torque to the receiver 32 and, thus, to the sump 20, in excess of the predetermined torque threshold which, in turn, can be set so as to ensure that the seal 42 properly engages the seal surface 40 of the receiver 32 when the plug 44 is in the sealed position 44A. Moreover, the configuration of the transverse outlet 50 of the plug 44 allows fluid to be drained from the sump 20 in a predictable direction, thereby promoting cleanliness and preventing undesirable fluid spillage and splatter which occurs when removing conventional drain plugs. In addition, those having ordinary skill in the art will appreciate that the operation of the torque limiter 48 between the configurations 48A, 48B, 48C affords significant opportunities for the use of innovative sump 20 technology, such as the implementation of exotic or unconventional materials, complex sump 20 geometry with baffles or oil control features, and the like, which might otherwise be cost-prohibitive in light of the risk of potential damage to the sump 20 caused by improper drain plug tightening. By way of non-limiting example, the present invention could allow effective implementation of sumps 20 manufactured at least partially from a composite materials with the receiver 32 formed integrally with the sump 20 or otherwise operatively attached to the sump 20, which would otherwise be unsuitable for use with conventional drain plugs due to the risk of cracking the sump 20 by overtightening the drain plug. In addition, it will be appreciated that the present invention affords improved opportunities for reducing the cost and complexity of manufacturing, assembling, and servicing sumps 20 used in connection with a number of different types of vehicle, fluid, and powertrain systems.

The present invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described. 

What is claimed is:
 1. A drain plug assembly for use in draining fluid out of a receiver operatively attached to a sump, said drain plug assembly comprising: a plug adapted for threaded engagement with the receiver and having a transverse outlet arranged for fluid communication with the sump, said plug being rotatable about an axis between a sealed position where fluid in the sump is inhibited from flowing across said outlet, and a drain position where fluid in the sump is permitted to flow across said outlet transverse to said axis; a head coupled to said plug and arranged for rotation in opposing first and second rotational directions in response to rotational torque applied to said head; and a torque limiter interposed between said head and said plug, said torque limiter being operable between: a lock configuration where said head and said plug rotate concurrently in said first rotational direction to move said plug toward said drain position in response to rotational torque applied to said head in said first rotational direction, a limit configuration where said head and said plug rotate concurrently in said second rotational direction to move said plug toward said sealed position in response to rotational torque applied to said head in said second rotational direction being less than a predetermined torque threshold, and a slip configuration where said head rotates independent of said plug in said second rotational direction to interrupt rotation of said plug in response to rotational torque applied to said head in said second rotational direction being greater than said predetermined torque threshold.
 2. The drain plug assembly as set forth in claim 1, wherein said plug further comprises a shank extending along said axis to a shank end; and wherein said outlet is formed in said shank arranged axially between said shank end and said head.
 3. The drain plug assembly as set forth in claim 2, wherein said outlet is formed in said shank transverse to said axis to direct fluid flowing across said outlet away from said axis when said plug is in said drain position.
 4. The drain plug assembly as set forth in claim 2, wherein said plug further comprises: an inlet formed in said shank adjacent to said shank end; and a channel formed in said shank extending in fluid communication between said inlet and said outlet to permit fluid in the sump to flow across said inlet, along said channel, and across said outlet when said plug is in said drain position.
 5. The drain plug assembly as set forth in claim 1, wherein said plug further comprises a coupler arranged to support said head for rotation about said axis and shaped to inhibit axial movement of said head with respect to said plug.
 6. The drain plug assembly as set forth in claim 1, wherein said torque limiter includes a torque receiving element operatively attached to said plug, and a torque delivery element operatively attached to said head and disposed in engagement with said torque receiving element such that said head and said plug rotate concurrently in response to rotational torque applied to said head in either of said first and second rotational directions being less than said predetermined torque threshold.
 7. The drain plug assembly as set forth in claim 6, wherein one of said torque receiving element and said torque delivery element comprises a plurality of splines arranged radially about said axis, and the other of said torque receiving element and said torque delivery element comprises a plurality of resilient cogs arranged radially about said axis; wherein said plurality of resilient cogs engage said plurality of splines to facilitate concurrent rotation of said head and said plug when said torque limiter operates in one of said lock configuration and said limit configuration; and wherein said plurality of resilient cogs are shaped so as to deflect to interrupt concurrent rotation of said head and said plug when said torque limiter operates in said slip configuration.
 8. The drain plug assembly as set forth in claim 6, wherein said torque delivery element comprises at least one resilient cog extending radially away from said axis and defining a brace surface; and wherein said torque receiving element comprises at least one spline defining a flat surface arranged to abut said brace surface of said at least one resilient cog to facilitate concurrent rotation of said plug and said head in said first rotational direction when said torque limiter operates in said lock configuration.
 9. The drain plug assembly as set forth in claim 8, wherein said at least one resilient cog of said torque delivery element further comprises a cam surface; and wherein said at least one spline of said torque receiving element further comprises a ramp surface arranged to abut said cam surface of said at least one resilient cog to facilitate concurrent rotation of said plug and said head in said second rotational direction when said torque limiter operates in said limit configuration.
 10. The drain plug assembly as set forth in claim 9, wherein said at least one resilient cog of said torque delivery element is shaped to deflect away from said at least one spline to bring said cam surface of said at least one resilient cog out of abutment with said ramp surface of said at least one spline when said torque limiter operates in said slip configuration.
 11. A system for use in draining fluid from a sump, said system comprising: a receiver adapted for attachment to the sump, said receiver extending along an axis between opposing first and second ends and comprising a bore extending between said first end and said second end, a drain port arranged between said first end and said second end and disposed in fluid communication with said bore, a first seal surface arranged between said first end and said drain port, and a second seal surface arranged between said drain port and said second end; and a drain plug assembly for draining fluid from the sump, said drain plug assembly comprising: a seal arranged for engagement with said first and second seal surfaces of said receiver; a plug supporting said seal, disposed in threaded engagement with said receiver, and having an outlet arranged for fluid communication with the sump, said plug being rotatable about said axis between a sealed position where said seal engages said first seal surface of said receiver to inhibit fluid in the sump from flowing across said outlet, and a drain position where said seal engages said second seal surface of said receiver to allow fluid in the sump to flow across said outlet and out of said drain port of said receiver; a head coupled to said plug and arranged for rotation in opposing first and second rotational directions in response to rotational torque applied to said head; and a torque limiter interposed between said head and said plug configured to translate applied rotational torque from said head to said plug to move said plug between said sealed position and said drain position, and further configured to interrupt rotation of said plug in response to rotational torque applied to said head exceeding a predetermined torque threshold.
 12. The system as set forth in claim 11, wherein said plug of said drain plug assembly further comprises a mount supporting said seal, and a shank extending along said axis to a shank end; and wherein said outlet is formed in said shank arranged axially between said shank end and said head to permit fluid in the sump to flow across said outlet and out of said drain port of said receiver when said plug is in said drain position.
 13. The system as set forth in claim 12, wherein said drain port of said receiver and said outlet of said plug are each formed transverse to said axis to direct fluid flowing across said outlet away from said axis and out of said drain port of said receiver when said plug is in said drain position.
 14. The system as set forth in claim 12, wherein said plug of said drain plug assembly further comprises: an inlet formed in said shank adjacent to said shank end; and a channel formed in said shank extending in fluid communication between said inlet and said outlet to permit fluid in the sump to flow across said inlet, along said channel, across said outlet, and out of said drain port of said receiver when said plug is in said drain position.
 15. The system as set forth in claim 11, wherein said torque limiter of said drain plug assembly includes a torque receiving element operatively attached to said plug, and a torque delivery element operatively attached to said head and disposed in engagement with said torque receiving element such that said head and said plug rotate concurrently in response to rotational torque applied to said head in either of said first and second rotational directions being less than said predetermined torque threshold.
 16. The system as set forth in claim 15, wherein one of said torque receiving element and said torque delivery element comprises a plurality of splines arranged radially about said axis, and the other of said torque receiving element and said torque delivery element comprises a plurality of resilient cogs arranged radially about said axis; wherein said plurality of resilient cogs engage said plurality of splines to facilitate concurrent rotation of said head and said plug when rotational torque applied to said head is less than said predetermined torque threshold; and wherein said plurality of resilient cogs are shaped so as to deflect to interrupt concurrent rotation of said head and said plug when rotational torque applied to said head is greater than said predetermined torque threshold.
 17. The system as set forth in claim 11, wherein said bore of said receiver further comprises: a first cylindrical region disposed adjacent to said first end of said receiver, at least partially defining said first seal surface, and having a first inner diameter; and a second cylindrical region disposed adjacent to said second end of said receiver, at least partially defining said second seal surface, and having a second inner diameter larger than said first inner diameter.
 18. The system as set forth in claim 17, wherein said seal of said drain plug assembly has an outer seal diameter larger than said first inner diameter of said bore of said receiver such that said seal is compressed between said plug and said first seal surface of said receiver when said plug is in said sealed position to prevent fluid from flowing out of the sump.
 19. The system as set forth in claim 17, wherein said seal of said drain plug assembly has an outer seal diameter larger than said second inner diameter of said bore of said receiver such that said seal is at least partially compressed between said plug and said second seal surface of said receiver when said plug is in said drain position to prevent fluid in the sump from flowing out of said second end of said receiver as fluid from the sump flows across said outlet of said plug and out of said drain port of said receiver.
 20. The system as set forth in claim 17, wherein said bore of said receiver further comprises a tapered region extending between said first cylindrical region and said second cylindrical region to promote compression of said seal between said plug and said first cylindrical region of said receiver as said plug moves toward said sealed position.
 21. The system as set forth in claim 17, wherein said drain port of said receiver is formed at least partially in said second cylindrical region of said receiver.
 22. The system as set forth in claim 21, wherein said drain port of said receiver is disposed in spaced relation with said first cylindrical region of said receiver.
 23. The system as set forth in claim 11, wherein said torque limiter of said drain plug assembly is operable between: a lock configuration where said head and said plug rotate concurrently in said first rotational direction to move said plug toward said drain position in response to rotational torque applied to said head in said first rotational direction, a limit configuration where said head and said plug rotate concurrently in said second rotational direction to move said plug toward said sealed position in response to rotational torque applied to said head in said second rotational direction being less than said predetermined torque threshold, and a slip configuration where said head rotates independent of said plug in said second rotational direction to interrupt rotation of said plug in response to rotational torque applied to said head in said second rotational direction being greater than said predetermined torque threshold. 